Astronomy final
Q4.12* From your textbook's chapter 9.3, describe the evidence in the lunar maria and highlands that indicates the cratering rate on the Moon hasn't always been constant, but instead there was an early era of heavy bombardment, then a slower, constant rate from that point forward.
The highlands should have about the 10 times the amount of impacts then the Maria but the radioactive dating puts them around the same age, if the impacts were to be constant then the age of the moon would be older then the universe
Q4.23* From the Scientific American article "Mars in Motion," another type of feature observed on Mars is the "Recurring Slope Lineae" (or RSL). Describe two arguments to suggest these are associated with flowing water (one from page 62, one from page 65).
The temp of southern mars can be warm enough to support water if the air wasn't so thin. as mars heats only the saltiest ice remains, when the sun hits the slopes it melts away the salty ice which would show the salty water.
Q4.25* From the Scientific American article "How to Search for Life on Mars," (a) describe how the first Viking experiment searched for life in the Martian soil, and (b) explain how the presence of perchlorate in the soil explains the "false positive" results from Viking.
The viking took a a scoop of soil and added carbon compounds for food for any mico-organisms that might be there. it looked for signs of photo synthesis, added water into soil to see if c02 reaction would happen, instead it say o2 output. Perchlorate is a very reactive molecule, the fuel from the lander would have obliterated all life forms, the make up of perchlorate explains each of the vikings discoveries
Q1.7* From the reading "Philosophy and the Scientific Method," (a) explain one of the benefits of irrefutable ideas and also (b) explain the major weakness of a system of knowledge based upon irrefutable ideas.
a) compelling, secure, and explained, able to reach a consensusb) one irrefutable idea can contradict another with no decisive way to choose
Q2.13* From your textbook's chapter 7.3, (a) describe how we estimate how old a planetary surface is (how long since it has undergone a major change). Also, (b) describe how we determine the age of a rock (how long ago it solidified). Specifically for (b), what three things do we have to know in order to estimate the solidification age of a rock?
a) count the number of craters since impacts have been roughly consistent and measure the age of individual rocksb) how much of a radioactive parent element is left, how much of its daughter products have accumulated, and what its half-life is
Q1.43* From the decoding weather video, we find there is an imbalance in carbon. When we calculate how much carbon we are emitting, only about half of it shows up in the atmosphere, so we want to know where the rest of the carbon goes. Explain (a) how Dr. Greg Asner is attempting to answer this question (what instrument does he use and what does he measure), and (b) explain about what fraction of emitted carbon is being accounted for with Asner's measurements.
a) he uses lasers to reconstruct the forest in 3D and it allows you to see the chemicals in each individual tree, his instrument shows areas of high and low carbonb) trees are soaking up about 1/4 of the carbon dioxide we are putting into the atmosphere each year
Q2.9* From your textbook's chapter 6.4, (a) explain why radio telescopes typically have much worse resolution than optical telescopes, and (b) briefly describe how interferometry can be used to overcome this problem.
a) radio waves have such long wavelengths and the longer the waves, the harder it is to resolve fine details in images or mapsb) uses multiple smaller radio telescopes as part of one whole image that all coordinate to make one image, need very accurate timing
Q1.50* From lecture, what is (a) the major benefit and (b) the major drawback of a system of knowledge based upon scientific principles?
a) science is testable and can bring about a consensus supported by research and evidenceb) science is often wrong and always being improved upon
Q1.27* From the Scientific American article "The Permafrost Prediction," if the permafrost in a given region thaws, (a) not all of its Carbon will be released and (b) what is released will be released slowly over decades or centuries. Explain each of these two claims (the first two of three key questions posed about Carbon release in the article).
a) some fraction of the carbon will remain in the ground because it is so inaccessible or inedible for microbesb) the carbon is already in a semidecomposed state and the microbes only further degrade slowly
Q4.22* From the Scientific American article "Mars in Motion," the "gullies" observed frequently on Mars were originally thought to be some manifestation of flowing water (though there were problems with this hypothesis as mentioned at the opening of the article). Eventually, the HiRISE mission came up with enough observational data to convince scientists that the gullies are caused by sublimation of carbon dioxide frost. Explain two lines of evidence that led scientists to this conclusion.
gullies match the seasonal play of c02 frost, when you find one you often find the other. the gullies form by the co2 causing rock soil to flow downhill like a liquid. The RSL saw it happen by ground warmth not warmth from the sun.
Q5.21* From the "Interstellar Interlopers" article, describe three differences between the 2nd interstellar object (2I/Borisov) and Oumuamua that indicate Borisov is more like the kind of object we expected to find.
it appears much like a typical comet in shape and movement the comet releases gasses as ice sublimates off its surface origin of the planet is thought to be from the old outer edge of a distant solar system
Q4.43* From the video "Crash Course - Mars:" why does the narrator argue that life could have potentially formed on Mars even before it formed on Earth, billions of years ago?
it is possible because mars is smaller so it cooled much faster with life forming after the cooling like it did on earth. all of the ingredients were there. curiosity detected a spike in methane- a gas produced by life.
Q5.28* From the video "Crash Course: Saturn," explain what properites of the lakes on the surface of Titan make us think there is active weather in the atmosphere of Saturn's moon Titan
the changing of shorelines lapping of waves, waves coming in and going out the same way water does on earth. there is also an atmosphere and a abundance of organic carbon based molecules.
Q5.23* From the video "Crash Course: Jupiter," explain the two different theories we currently have about how Jupiter formed (and what kind of core it has).
the disk collapsed in several places forming huge clumps which collided and stuck together forming the planet which means it may not have a core at all. several large rocky proto-planets collided then drew in the gas we see today.
Q4.13* From your textbook's chapter 9.5, describe how radar measurements of Mercury revealed its rotation rate to astronomers on Earth (explain or use a simple diagram to show what the observations would look like if Mercury were rotating slowly vs quickly and explain the difference).
the part of the pulse comes back differently, some reflection redshifts wile some blue shifts
Q5.16* From your textbook's chapter 14.1, (a) what is the radiant of a meteor shower? (b) What causes the radiant effect that makes meteor trails all seem like they originate from (or point back towards) a specific place on the sky?
the radiant is a Darrell line that appears to come toward us from a singular point in the sky the effect is caused by the constellation by the meter shower can happen anywhere.
Q3.18* From the Scientific American article "A Planet is Born," what is the main weakness (or bias) in the two most popular exoplanet detection techniques (transit and radial velocity), and how do the observations of the ALMA telescopes enable us to spot solar systems more like our own?
the weakness is that we must see the planet orbit the star. we would be waiting a very long time and would miss lots of other planets. we can use alma to spot disks in far orbits and see if they are being disturbed by orbiting material
Q5.51* From lecture, explain what are the Kirkwood gaps and how they are formed. As part of your answer, explain why an asteroid in one of the gaps would be affected so radically while an asteroid just to one side or the other of the gap isn't affected.
they are gaps in the distribution of orbital periods. caused by the gravitational interaction between Jupiter and asteroids in the periods
Q5.13* From your textbook's chapter 13.2, we learn that discoveries small asteroids that may be hazards to the Earth is very difficult, so it is important to know as we find them, how many more are still left to be discovered. Describe two ways in which we know that our surveys to date have found roughly 90% of these hazardous asteroids larger than 1 kilometer in size.
they study the craters on the lunar Maria, which allows us to estimate the amount of impacts in the last billion years. they study the survey to see how often they are rediscovering asteroids, when they began they were all new but as they progressed they began to see fewer and fewer new findings
Q3.3* From your textbook's chapter 21.4, explain how we deduce the approximate size (or radius) of transiting exoplanets. Also, how do we deduce the density of these exoplanets in order to determine whether they are rocky or gaseous?
we can find out size using the transit method. we can find the density by using the doppler and transit methods together. we can compare density of our own planets to find what these planets could be made of.
Q5.49* From lecture, normally, when a comet's orbit is different than we expect, it is because of something like the Yarkovsky Effect mentioned in question 6.19. Explain two reasons why we do not believe cometary jets are the cause of Oumuamua's peculiar path through the solar system.
we dont see any evidence of a jet on the comet if it had jets the rotation would change, the rotation doesn't change so there is no jets
Q5.50* From lecture, explain why Iridium is more common in the interior of the Earth than in the surface rocks and crust of the Earth.
when the earth was forming heavier materials sank towards the center of earth. an impact distributed the cosmic amount of iridium over earths surface. known at the KT boundary
Q3.25* From the Scientific American article "Alone in the Milky Way," explain two reasons why life is less likely to thrive on planets orbiting stars that are further from the center of the galaxy.
1) stars are sparser and metallicity is lower, so there are fewer rocky planets if any2) they are most likely out of the galactic habitable zone range
Q3.37* From the video "Life Beyond Earth, Part 1," Freeman Dyson explains that there are two possibilities regarding the origin of life. Either it came into being gradually through chemistry and steps we could hope to retrace (and could presumably be reproduced elsewhere) or life is some kind of extraordinary fluke. (a) If the answer to the question of the origin of life is the first possibility, what does that imply about life beyond Earth? (b) What if the answer is the latter possibility?
a) it should happen all over the cosmos, and we should be able to find lifeb) if it was a fluke, we won't find life elsewhere
Q3.53* From lecture, (a) once we have a graph of a star's radial velocity vs time, what two things on that graph do we measure? (b) For each of these two things, explain what property of the companion planet do deduce (explain why is there is a relation between what we measure and the property of the planet).
a) period and amplitudeb) period shows the distance between star and planet, amplitude shows the mass of the companion planet because the larger the planet the more the star moves around
Q1.28* From the Scientific American article "The Permafrost Prediction," if the permafrost in a given region thaws, some Carbon will be released from the soil, but it is also true that the same region will absorb more Carbon from the atmosphere. (a) Explain why, and (b) explain whether the net result is more Carbon added to the atmosphere or more absorbed from the atmosphere.
a) warming the ground helps microbes decompose carbon in the soil, but it also helps plants grow faster and larger which absorbs more carbon dioxideb) continued microbial activity through periods where plants are dormant shifts the balance to more carbon in the atmosphere
Q2.5* From the Scientific American article "Gather the Wind," explain how electrolyzers work. Specifically, (a) describe how the energy is stored, and (b) describe how a fuel cell releases this stored energy for later use.
a) water is split into hydrogen and oxygen by running an electric current through it, hydrogen is stored in a tankb) hydrogen can be consumed in a fuel cell where it is recombined with air and water to create energy
Q5.6* From your textbook's chapter 12.2, why aren't all four of Jupiter's major moons composed primarily of ice, given that ice was by far the most abundant solid substance in the outer solar system?
because of Jupiter itself, the heat and radiation that Jupiter gave off as well as its gravitational pull caused changes to the other moon.
Q4.17* From your textbook's chapter 10.4, a small sample of meteorites found on Earth's surface over many years is composed mostly of volcanic basalts. Explain the two arguments Astronomers have used to deduce that the meteorites likely originated from the surface of Mars.
by process of planet elimination 1.3 billion years ago there was no where else for them to come from. they were able to match the samples to properties that the viking provided with us.
Q3.5* From your textbook chapter 21.5, figure 21.23 is a bar chart showing the percentage of each category of planet size detected by the Kepler mission. Figure 21.24 is a bar chart showing the ACTUAL percentage of each category of planet size in the galaxy. Explain why these two bar charts are different (in other words, why are there more small-sized planets out there compared to what Kepler found).
they are different because the Kepler was unable to detect the small sized planets. they are also different because it doesn't show Kepler detections instead shows the average number of planets per star for solar type stars.
Q3.39* From the TESS Planet Hunter discover video, NASA scientists have created two possible models to represent TOI 700 d, the Earth-sized planet orbiting in the habitable zone of its parent star. They predict that the mostly-rocky planet will have an extra feature in its spectrum that wouldn't appear in a mostly-water planet model. What is the extra spectral signature?
- CH4 or methane- causes certain light to be filtered out of the spectrum and allows us to further research the possible conditions of the planet
Q2.45* From the video "Chasing Pluto," describe the theory proposed in the video that explains why Pluto is so small. Explain what interrupted its formation process.
- Pluto could have originally formed closer to the sun, but got pushed by larger planets to a more distant orbit- Pluto could also be a remain of the process of planet formation- stopped formation because it is so far from the sun, things are starting to freeze out like elements and the atmosphere
Q5.30* From the video "Kingdom of Saturn," name and explain three observed properties of Saturn's moon Enceladus that led us to believe there is liquid water in the interior near the South Pole of the moon.
- about 482 kilometers in diameter - the whitest body in the solar system - weak gravity - orbits in resonance with the moon
Q2.31* From the video on climate science, explain how Dave Montgomery and Anne Bickle's research into farming/gardening techniques may help reduce the overall amount of carbon in the atmosphere if adopted on a broad scale (talk about the example of Dave Legvold's farm).
- adopted no-till farming where farmers leave stuff on the ground after harvesting- as the stuff decays, nutrients seep into the ground and make the soil healthier- tilling releases carbon into the atmosphere
Q4.55* From lecture, explain how we use Argon to argue the Earth and Venus originally had similar atmospheres. Describe the logical sequence that starts with Argon measurements and ends with the conclusion that the two worlds had similar atmospheres originally.
- argon is a tracer gas because its abundance hasn't changed over time1) despite overall differences in atmospheres today, abundances of argon on earth and venus are the same2) since argon doesn't change over time, venus and earth had similar abundances of argon originally3) if argon was the same originally, so was H20, NH3, etc.
Q3.42* From the TED talk about ALMA,, one of the ALMA observations discussed is an observation of Carbon Monoxide snow around the newly formed star TW Hydrae. How is this related to the possible origin of life on Earth?
- comets can pick up carbon monoxide and organic molecules by passing through clouds that surround stars- the comets crash into planets, depositing the organic molecules- we believe one possibility for life on earth is things carrying organic molecules and elements crashed into earth
Q5.41* From the video "Asteroids," from the Arizona site and the Sudbury site, the video discusses 3 additional features, aside from those in the previous question, that are common indicators of impact sites. Describe each of these three, and briefly explain how the impact process results in each feature.
- crystalized sandstone rock - shutter cones that can only form from asteroid impact enriched iridium that forms in space
Q4.49* From lecture, briefly describe the capture theory for the origin of the Earth's moon, and explain two problems with the theory from a scientific standpoint.
- earth and moon formed independently and separately and then later the moon was captured by the earth- its too much of a coincidence that the moon has the same isotopic fingerprint as earth- the moon would be moving faster than the escape velocity so it would have to be slowing down for the captive theory to work
Q3.30* From the "Crash Course: Exoplanets" video: What was so significant about the discovery of the exoplanet HD 209458b, discovered in 1999? Explain.
- had only a 3.5 day orbit and we could view it edge-on, so we could use the Doppler shift method- the first independent confirmation of an exoplanet- 70% the mass of Jupiter and its tilt causes it to cross in front of its star so we can see it which is unlike other planets like it
Q2.25* From the Scientific American article "The Seven Year Mission," describe two reasons why the target for the OSIRIS-Rex mission was the asteroid Bennu.
- it is a coal-black mass of delicate organic compounds that could be precursors to our planet's carbon-based biochemistry- it is potentially hazardous and comes perilously close to earth
Q1.18* From the article "The Physical Science Behind Climate Change," explain the evidence found in computer models of the climate that indicate that natural climate forcings are not sufficient to explain the rise in average temperature since the mid-20th century and that anthropogenic (human-caused) factors must be largely responsible.
- models only using natural forcings are inaccurate- using both natural and human forcings makes the model accurate, proving people are changing temperatures
Q1.42* From the decoding weather video, explain how Dr. Andrea Dutton is able to reconstruct the history of temperature in the Earth's atmosphere over the past 800,000 years (explain how is oxygen used in the process).
- oxygen isotopes are split into O-16 and O-18- when is it colder oxygen is heavier, so rocks from periods when it is colder would have much higher concentrations of O-18 over O-16 and vice versa
Q2.29* From the video on climate science, explain how perovskites may fundamentally change the way we harvest solar energy, how it differs from using silicon.
- perovskites take energy from the sun and turn it into electricity- while silicon requires exacting production techniques, perovskites are easy to work with, come in a bottle, and just a few strokes of perovskite paint does the job
Q2.15* From your textbook's chapter 14.2, although iron-type meteorites account for only about 3% of meteorites that fall to the Earth, about 42% of meteorites that have been found on Earth are iron meteorites. Explain why this is true.
- pure iron almost never occurs naturally on earth, so a chunk of metallic iron is most likely a meteorite- stones are more common than iron meteorites, but they are difficult to recognize
Q4.50* From lecture, briefly describe the giant impact theory for the origin of the Earth's moon. How does the giant impact theory explain (a) the lack of metal in the Moon relative to the Earth, (b) the fact that Earth and Moon rocks have very similar isotope fingerprints, and (c) the relative lack of volatiles in lunar rocks compared to the Earth.
- shortly after earth formed, a big object crashed into it and a chunk of mantle flew off into space and formed the moona) earth's mantle is mostly rockb) piece of earthc) big impact caused heat which got rid of volatiles
Q2.49* From lecture, two other variables that are associated with costs are subsidies and future costs. Explain what subsidies are and why they help to make fossil fuels cheaper, and explain why fossil fuel use may have costs that are eventually paid by later generations (even though they will get no benefit from using the energy, obviously).
- subsidies: government assistance- subsidies pay about half of fossil fuel costs- fossil fuels put carbon dioxide in the air and will mess things up in the future and future populations will have to pay for environmental damages
Q3.59* From lecture, if we were to encounter or detect evidence (by finding artificial signals through our searches of the sky) another intelligent, communicative civilization besides our own, it is highly likely that that other civilization will be much more advanced than our own. Explain why they would likely be more advanced than us (this is also covered in OpenStax Chapter 30.4).
- survived long enough because they know how to stay quiet- it's unlikely they are also infants like we are in terms of lifetime- they will be at a random stage in their lifetime because we're so young its very likely that another civilization would be more advanced and further along
Q1.54* From lecture, (related to Q1.11 and Q1.12) use a graph of blackbody radiation to help explain why gases that block infrared light tend to warm the Earth due to the nature of the incoming and outgoing light (the blackbody curves).
- taller graph: incoming sunshine, 10% blocked and cools- smaller graph: outgoing earth shine, 50% blocked and warms- where smaller peaks and taller above: greenhouse gas blocked IR
Q2.24* From the Scientific American article "Secrets of Primitive Meteorites" -- Explain why the author concludes that our early solar system probably resembled the dusty disks surrounding a class of young stars known as T Tour stars.
- the author inferred roughly the locations where chondrite groups formed and the relative amount of dust in those regions- dust distribution resembles what is seen in disks of dust and gas swirling around T Tour stars- resemblance suggests that T Tour systems are good comparisons of the sun and its disks during early stages of solar system history
Q1.3* From the reading "Cargo Cult Science," how would you explain to the "cargo cult" people of the South Seas why the planes don't land? Answer in a simple, direct way: what are they doing wrong, or why is what they are doing not working? Hint: think about why the planes REALLY landed and what has changed.
- the cargo doesn't come back because the war is over- no matter the coconuts/sticks, cargo only comes when there is war
Q2.19* From the Scientific American article "What Is a Planet?" - In the year 1851, the number of planets had grown to 15. What were all of these extra planets and why were they eventually disqualified from planet status?
- the extra planets were all asteroids- scientists thought there should be objects in all the space between planets so they looked and found asteroids- there were too many planets and there was an exponential growth curve of the number of planets so they got demoted
Q3.49* From the film "Life Beyond Earth, Part 2," explain why it will be easier to communicate (or find) other intelligent alien civilizations if the average lifetime of a civilization is extremely long (millions or tens of millions of years) instead of short (less than 100,000 years or so).
- the longer alien civilizations last, the better our chance of communicating with them- if they last a long time, radio signals could reach them in time- if they only last a short period of time, there would only be a few planets "on air" at the same time they are, reducing the chances of making contact
Q3.22* From the Scientific American article "The Galactic Archipelago," explain why it would be difficult for us to determine whether or not an advanced civilization lived on our planet millions of years ago. What is an example of evidence we might plausibly find that would indicate the existence of a past advanced civilization on Earth?
- the only real evidence after a million or more years would boil down to isotopic or chemical stratigraphic anomalies and fossil remains are so rare and contingent on special conditions of formation that they might not tell us anything- synthetic molecules, radioactive fallout, fossil remains
Q2.23* From the Scientific American article "Secrets of Primitive Meteorites" - The author asserts that carbonaceous chondrites probably orbit furthest from the Sun compared to any other type of chondrite. Explain why the author thinks this is true.
- they are rich is organic compounds which means the meteorites formed far from the sun- being closer would have degraded the organic matter
Q2.34* From the video "Can We Cool the Planet," several scientists in the video discuss their efforts to understand the effects of geoengineering (e.g. making clouds bright or releasing reflecting particles high the atmosphere). Describe two potential drawbacks to this approach as a "solution" to human-caused climate change.
- unintended/unknown side effects- acts as a disincentive to pursue alternative energy and lower carbon dioxide emissions
Q3.20* From the short Scientific American article "The Earth Next Door," name and briefly explain three potential problems Proxima b might have due to its close orbit that may prevent the planet from providing a stable environment in which to host life?
- unstable and violent youths - it could have tidal locking forcing one side in the dark and there other in light in each orbit - tidal heating caused by it coming to close to a start would cause oceans to burn off.
Q1.23* From the article "The Last Great Global Warming," how do we know the temperature of the water at the time these ancient sediment deposits occured?
- water is a mix of different oxygen isotopes (O-16 and O-18)- the colder the water, the more heavy oxygen (O-18)
Q3.52* From lecture, in the Doppler wobble method of exoplanet detection, explain what we observe and how that turns into a graph of radial velocity vs time.
- we observe 5-10 minute intervals of time that measure the Doppler shift- looks like a sin graph and tells us radial velocity over time
Q3.27* From the Scientific American article "Alone in the Milky Way," although the appearance of life on Earth only a billion years into the planet's history would make us optimistic about discovering life elsewhere, the development of more complex life (like us) seems to be extremely unlikely because of the history of life's development since that first single-celled organism appeared. Explain why.
- we only say more complex organisms around 550 million years ago, even though there were single-cell organisms on earth about 3.5 billion years ago and merging bacteria and archaea which both remained mostly unchanged for a long time- if life takes that long to develop, the odds of finding life in a much earlier stage is more likely than finding complex life
Q1.35* From the "Flat Earth" video, in one popular variant of the Flat Earth theory, our apparent weight is not caused by gravity but rather a constant upward acceleration of the flat disk of the Earth. Describe an observational fact that refutes this model.
- when you measure the strength of gravity, it varies on different places of the earth- different gravitational pulls refute the idea that we are accelerating through space
Q5.3* From your textbook's chapter 11.2, how do we know Saturn has an additional internal heat source not found on Jupiter?
-because of the size of the heat source, it is half the size of Jupiters but produces twice the amount of energy -the source is helium separating from hydrogen
Q5.4* From your textbook's chapter 11.3, explain what causes the color difference between the light and dark bands in the atmosphere of Jupiter.
-the difference is caused by upwelling air causing light clouds and darker belts are caused by cooler atmosphere moving downward completing the convection cycle
Q1.19* From the article "The Physical Science Behind Climate Change," explain two patterns in our atmosphere that the authors consider to be a fingerprint of human influence, showing humans are caused the changes and not natural sources (like changes in solar activity).
1) greater warming over land than ocean and at sea surface than in deeper layers2) while the troposphere has warmed, the stratosphere above it has cooled
Q1.21* From the article "The Last Great Global Warming," after an initial buildup of Carbon Dioxide in the atmosphere caused perhaps by volcanic eruptions 56 million years ago, describe three other changes that occured (likely due to the initial Carbon buildup) to add even more heat-trapping gases to the atmosphere in a geologically short time (thousands of years).
1) mixing of ocean leads to more methane gas2) droughts lead to wildfires that release carbon dioxide3) melting permafrost releases carbon dioxide
Q1.29* From the Scientific American article "Meltdown," we learn that when "permanent" ice melts (either on the ocean or on land) due to warming, feedback effects from this can cause even more warming. Explain three ways the melting ice causes further warming in the Arctic.
1) more dark ocean is exposed when ice melts which makes it warmer2) thawing soil can release large quantities of heat-trapping gases3) permafrost melting releases carbon dioxide
Q1.22* From the article "The Last Great Global Warming," describe the two chemical changes that occured in the oceans due to the buildup of CO2 in the atmosphere.
1) surplus of carbonic acid (acidification)2) less oxygen in oceans
Q4.58* From lecture, describe the evidence (3 parts) from the Magellan explorer that led scientists to the conclusion that Venus resurfaced itself somehow about 500 million years ago.
1) venus has about 5x more craters than earth so the solidification age of venus' surface is about 500 million years2) craters are distributed uniformly on venus so the entire surface of venus was solidified at the same time3) craters on venus show no sign of erosion or decay so there must have been a large, quick catastrophe since there is no gradual way to erase craters
Q5.59* From lecture, explain the four lines of evidence that indicate some kind of catastrophic event in the Saturn system about 100 million years ago.
1- lifetime of rings can't be much older than 100 million years, ring particle orbits are unstable due to collisions 2- rings are very bright, made mostly of ice, if rings were more than 100m years old they would accumulate dust and be darker 3- titan suffered major collisions in recent past due energetic orbit 4- crater density on surface indicates a solidification age of roughly 100 million yrs
Q5.35* From the video "The Bizarre Characteristics of Titan," explain what is thought to be the cause of Titan's orbital eccentricity and tilted orbital plane.
In the beginning there was several other moons, all of the collisions caused titan to have different orbit and eccentricity because it was last one standing.
Q4.40* From the video "Venus Could Have Supported Life for Billions of Years:" in the simulation described in the video, Venus is supposed to have started with a thick atmosphere of mostly Nitrogen and oceans of water all over the surface. What did the simulations show about the long-term evolution of Venus' atmosphere over the first 3 billion years or so of its history (asking specifically about temperatures and carbon dioxide levels)?
In those 3 billion years Venus was able to keep a stable temperature, range temp of max 50c-20c. The planet had a carbon atmosphere but over time the carbon was stored in silicate rocks only to be released by volcanic event causing a runaway gas effect on the planet.
Q4.37* From the video "Crash Course: Tides," what causes "extra high" high tides, even higher than what you would normally see during Spring tides? These kinds of tides are called proxigean tides.
It is when the moon is closet to us at a new or full moon making the tides even stronger, which causes the proxigean tides
Q4.28* From the Scientific American article "How to Search for Life on Mars," describe two important factors that make it more probable for life to be present, which will then help us to select a landing site for this proposed mission to Mars.
Place with ice and salt that would protect organisms from decay area with lower ionizing radiation so there is still life
